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Patented June 28, 1932 PATENT Fries ROBERT KUNZ, OF FISGHLHAM, AUSTRIA,ASSIGNOR TO THE FIRM O]? ETEBNIT ING,

. OF ST. LOUIS, MISSOURI PROCESS FOR MANUFACTURING ARTIFICIAL STONEPLATES OF FIBBOCiS MATERIALS I AND HYDRAULIC CEMENT No Drawing.Application filed March 28, 1929, Serial No. 850,818, and in AustriaNovember 23, 1928.

The present invention relates to the manufaeture of artificial stoneplates from fibrous material by means of hydraulic cement.

It is known tomanufacture artificial stone plates of fibrous materialsand hydraulic cement by mixing fibrous asbestos with a substantialexcess of cement and water, treating the mixture in the paper machine,winding up the moist web or sheet of material upon a 1 drum, cutting offplates of a desired size and subjecting the plates to high pressure.After the setting of the cement the plates manufactured in the aforesaidmanner will acquire a high strength, they are extraordinarily dense,durable and light if required the plates may also be nailed. A certaindrawback of the asbestos cement plates of the before men tioned kind isthat they disintegrate under the sudden influence of high temperatures,

this fact being of considerable inconvenience manufacturing artificialstone plates; the improved process allows of obtaining on the papermachine, from fibrous materials, hydraulic cement and water,. artificialstone plates of any desired thickness, which do not have the abovementioned disadvantages but may be heated when exposed to immediateaction of an open flame, so as to become incandescent without changingsensibly, especially without bursting. I have made the surprisingobservation that it is suflicient to incorporate into the plates a smallquantity of an oily or fatty substance, i. e. mineral oil or vegetableoil or animal fat to impart to them the desired fire proofness. Themineral oil or the like can be added in any phase of the process, thatis, it can be either admixed in the vat or in the stirring box, orsprinkled on the web or sheet of material, while it is formed on thepaper machine, or on the moist asbestos cement pulp wound up on thewinding drum. Experiments continued for a long time have shown that theabove mentioned addition has no unfavorable influence on the setting andhardening of the cement, nor does it injure in any way the qualities ofthe finished plates.

The process of manufacturing artificial stone plates from fibrousmaterial and laydraulic cement under admixture of an oil is, thereforecharacterized thereby that the mixture of hydraulic cement, fibrousmaterial and water is treated in a well known manner on the papermachine, and that the oil is added in any desired phase of the saidrocess, for the purpose of obtaining artificial stone plates, which donot burst under the influence of heat- Although fatty oils may likewisebe used for the intended purpose, the process is preferably carried outby using mineral oils. As regards the properties of the mineral oils tobe used I have found that oils of different quality may be applied. Arefined light mineral oil of the viscosity 4, 5 at a temperature of 122F., and of an inflammation point 392 F. of the kind, which is frequentlyused as lubricating oil for bearings of speedy running machine parts ofsmall weight has proved to be very suitable. The quantity of added oilamounts to about 5 per cent of the weight of the solid constituents ofthe plates.

It is already known to use asphalt, bitumen, parafiine and the like forincreasing the compactness of articles manufactured from cement, orcement with different additions, by admixing these substances to thebulk or applying them to the surface of said articles. It hasfurthermore been proposedto manufacture plates from cement and asbestoshaving short fibres, or asbestos powder under admixture of' mineraloils. In this case, however, fibrous asbestos is not used and the treatment is not carried out. on the paper machine but the mixture of cementand asbestos is uniformly mixed with mineral oil and some water and thenforced through the mouthpiece of a press, the added mineral oil actingas a lubricant. In this process'the cement only amounts to from onethird to one half of the dry mixture, whereas in working on the Gilpaper machine the cement amounts to a quantity exceeding by far that ofthe fibrous asbestos.

What I claim is 1. Laminated artificial stone plates, consisting of amixture of hydraulic cement and water with fibrous material and anaddition of oil, which will not burst when heated to incandesccnce by anopen flame.

2. Laminated artificial stone plates, consisting of a mixture ofhydraulic cement and water with fibrous material and an addition ofmineral oil, which will notburst wlienheated to incandescence by an openflame.

3. Laminated artificial stone plates, con- 7 sisting of a mixture ofhydraulic cement and water with asbestos and an addition of oil, whichwill not burst when heated to incandescence by an open flame.

l. The process for manufacturing artificial stone plates which comprisesmixing a hydraulic cement and water with a long fibered asbestos,forming the mixture into a web on a paper making machine, and sprinklinga light oil on the web.

5. The process of manufacturing artificial stone plates which comprisesmixing a hydraulic cement and water with long asbestos fibers, formingthe mixture into a web on a paper making machine, and adding a quantityof light oil amounting to about five percent of the weight of the solidconstituents at any phase of the process.

6. The process of manufacturing artificial stone plates which comprisesforming a mixture of hydraulic cement, water and long fibers ofasbestos, forming sheets of said mixture, adding an oil to said mixtureduring any stage of the process, and forming a lami nated plate of saidsheets whereby the stone plates are prevented from bursting by influenceof heat.

7. The process of manufacturing artificial stone plates which comprisesforming a mixture containing water, long asbestos fibers, and a largeramount of hydraulic cement than asbestos, forming said mixture into athin sheet on a paper making machine, adding to said sheet about fivepercent of the weight of said solid constituents of oil, forming alaminated plate of a plurality of sheets formed as specified, subjectingsaid plate to pressure, and permitting the cement to set.

In testimony whereof I aflix my signature.

ROBERT KUN Z.

